<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>

    <style>
        div {
            width: 100px;
            height: 100px;
            animation: 2s linear 0s infinite  running change;
        }
      
        @keyframes change{
          0% {
            background: red;
          }
          100% {
            background: blue;
          }
        }
      </style>
</head>
<body>
    <div></div>
</body>
</html>